Abstract:

BACKGROUND: Our studies have confirmed that the exogenous bis-(3'-5')-cyclic dimeric guanosinemonophosphate (c-di-GMP) could inhibit the formation and adherion ability of Streptococcus mutans biomembrane. However, it is not clear whether c-di-GMP inside of streptococcus mutans has the same effect.
OBJECTIVE: To construct gcp gene inactivation strain of c-di-GMP within Streptococcus mutans and to observe the biological characters of Streptococcus mutans with gcp gene inactivation strain.
METHODS: Streptococcus mutans with gcp gene inactivation strain and wildlife mushroom supension were cultured on 96-well plates in anaerobic environment for 48 hours. The attached bacteria were stained with crystal violet, and ethanol/acetone dissolved the precipitated stain. The absorbance value at 575 nm was measured to represent the amount of biomembrane formation; Streptococcus mutans with gcp gene inactivation strain and wildlife mushroom were labeled by fluorescence; and then co-cultured with the hydroxylapatite coated with saliva. The fluorescence value of hydroxylapatite was detected and the adhesion rates between them were compared.
RESULTS AND CONCLUSION: The number of biomembranes in gcp gene inactivation strain was lower than that in wildlife mushroom; the adhesion rate on the surface of hydroxylapatite coated with saliva in gcp gene inactivation strain was lower than that in wildlife mushroom (P < 0.05). These findings suggest that the inactivation of gcp gene can inhibit the biomembrane formation of Streptococcus mutans and the adhesion on the surface of hydroxylapatite.